Single-Step Capture and Targeted Metabolomics of Alkyl-Quinolones in Outer Membrane Vesicles(OMVs) of Pseudomonas Aeruginosa.

Abstract

Outer membrane vesicles (OMVs), also called as bacterial membrane vesicles (BMVs), are secreted by many Gram-negative bacterial pathogens. These nanoscale vesicles traffic discrete arrays of virulence factors that can often induce complex pathologies far from the infection sites. The OMVs of P. aeruginosa, often regarded as the gold standard of BMVs are known to traffic a battery of specific small MW alkyl-quinolones (AQs). These AQs function like primordial hormones by modulating intra-species and inter-species bacterial interactions. They can also perform cross-kingdom signaling with the human host and directly exacerbate pathogenesis. The discrete isotopic signatures of AQs enjoy potential in the mass spectrometry-based diagnosis P. aeruginosa infections. Matrix-free laser desorption/ionization mass spectrometry (LDI-MS) presents a robust, cost-effective platform to fit this demand. We describe a LDI-MS system using inert ceramic filters that performs dual role of single-step enrichment of OMVs and matrix-free ionization/identification of AQs in situ.